Furnace-regulator system



Mar. 27, 1923. 1,449,885.

0. A. BODDIE.

FURNACE REGULATOR SYSTEM.

FILED AUG.26| 1919.

l l l A A A 23-- L L l A 7 9 /3 m 5 g S 1 l O 1 WITNESSES: INVENTOR I f/Jd/iamwu (/0/6/7662450/4/6 ATTORNEY Patented Mar. 27, 1923.

UNITED STATES PATENT OFFICE,

CLARENCE A. BODDIE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

FURNACE-REGULATOR SYSTEM.

Application filed August 26, 1919. Serial No. 319,909.

T 0 all whom it may concern:

Be it known that I, CLARENCE A. Booms, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Furnace-Regulator Systems, of which the following is a specification.

My invention relates to regulator systems and particularly to regulator systems for governing the movable electrodes in electric furnaces.

One object of my invention is to provide a furnace-regulator system that shall govern each movable electrode to maintain substantially constant current flow through it and that shall be provided with switch members which are selectively and intermittently operated to effect a step-by-step movement of the electrode to prevent overtravel.

Heretofore, it has been customary, in certain types of electrode furnaces, to operate each movable electrode of the furnace by a motor and to control the circuit of the motor by an oscillating member which is directly controlled by a main magnet in accordance with the current flowing through the electrode. Such furnace regulation has proved defective and impractical incertain respects; inasmuch as the oscillating mechanism must be somewhat cumbersome if adapted to carry the motor current and control the circuit of the motor and, moreover, no means is provided for effecting a quick stopping of the motor.

In a furnace-regulator system constructed in accordance with my invention, each electrode is raised and lowered by an electrode motor which is controlled by two electrically operated switches. The, two switches are controlled by a main magnet in accordance with the current flowing through the electrode and by an oscillating member to effect a step-by-step movement of the electrode to guard against any overtravel. Moreover the switches are provided with auxiliary contact members for completing a dynamic-braking circuit through the electrode motor to effect a quick stopping of such motor when the switches-are simultaneously de-energized. It will be noted that, by controlling the electrode motor through switches, it is possible to construct the main Control mechanism of a much lighter design so that the same is quicker and more accurate in its operation. Moreover, the switch members provide means for completmg a dynamic-braking circuit to effect quick stopping of the electrode motor.

The single figure of the accompanying drawing is a diagrammatic view ofa regulator system constructed in accordance with my invention.

Referring to the drawing, an electric fur nace 1, comprising a receptacle 2 containing a bath of material 3 and three movable electrodes 4, 5 and 6, is directly'connected to a three-phase supply circuit comprising conductors 7, 8 and 9.

Each electrode l, 5 and 6 is provided with a motor for raising and lowering it and a regulator for governing the operation of the motor to maintain a constant current flow through the associated electrode. Inasmuch as each electrode is operated in a similar manner by the motor and the regulator associated with it and inasmuch as each motor and each regulator are similar in construction and operation, it is deemed sufiicient to illustrate and describe the operation of only one electrode by the motor and the regulator associated with it.

A motor 10, comprising an armature l1 and a field winding 12, is provided for raising and lowering the electrode 2 in any suitable manner, as by means of a winding reel 13 and a flexible connector 14 which passes over a pulley 15 and is directly connected to the electrode 5. The field winding 12 is directly connected across an auxiliary sup circuit comprising conductors 16 and I7 and the armature 11 is selectively connected to the supply conductors 16 and 17 by means of switches 18 and 19.

' A main control magnet 20 and an oscillating mechanism 21 are provided for governing the operation of the switches ,18 and 19 in accordance with the current flowing through the electrode 5 to maintain a substantially-constant current flow through the electrode. The main magnet 20 comprises a winding 22 which is connected to the three-phase supply conductor 8 by means of a current transformer 23 in order to be energized in accordance with the current flowing through the electrode 5. A core armature 24, which is operated by the winding 22, is pivotally connected to a trip arm 25 and is provided with a dash pot 26 for adjusting the speed of its operation. The trip arm 25 is fulcrumed at 27 and carries a suspended trip member 28 for a purpose to be hereinafter set forth.

The oscillating mechanism 21 comprises a plate 29 which is rotatably mounted upon a shaft 30 and a contact wheel 31 which is also rotatably mounted .on a shaft 30 and is adapted to be connected to the plate 29 under certain conditions so as to be given an oscillatory movement in accordance with the operation of the plate 29. The plate 29 carries two dog members 32 and 33 which are biased into engagement with pins 34 and 35 by means of spring members 36 and 37. Moreover, the oscillating plate 29 carries two pawls 38 and 39 which are normally maintained in engagement with the two dogs 32 and 33 by means of two spring members 40 and 41. The two pawls 38 and 39 are respectively provided with lugs 42 and 43 which are adapted to engage stationary pins 44 and 45 in certain positions of the oscillating plate 29 to reurn the pawls to normal position to be engaged and held by the dogs 32 and 33. The stationary pins 44 and 45 project through slots in the plate 29 in order not to interfere with the oscillatory movement of the plate. When the plate 29 is in a neutral position, as shown in the drawing, the increased energization of the main magnet 20 will operate the trip arm 25 to lower the trip member 28 to engage the top portion of the dog 32. When the dog 32 engages the trip member 28 and the plate 29 is moved toward the left, as shown in the drawing, the dog is given a movement in a clockwise direction to release the pawl 38, for a purpose to be hereinafter set forth. In case the trip member 28 is raised by reason of a decreased current flowing through the circuit of the electrode 5, the trip member is alined with the top portion of the dog 33 so that a movement of the plate 29 to the right, as shown in the drawing, will give the dog a movement in a counter-clockwise direction to release the pawl 39 for a purpose to be hereinafter set forth.

An auxiliary motor 47, comprising an armature 48 and a field winding 49, is provided for efiecting an oscillatory movement of the plate 29. The armature 48 is provided with a shaft 49 carrying a pulley 50 which is belted to a second pulley 51. The second pulley 51 is provided with a crank disk 52 which is directly connected to the plate 29 by means of a connecting rod 53. It is to be understood that any other suitable or well-known means may be provided, in place of the motor 49 and the connecting means shown, for effecting an oscillatory movement of the plate 29.

The contact wheel 31 is provided with accesses a contact arm 54 that carries a main con tact member 55 which is adapted to engage contact members 56 and 57, according to the position of the contact wheel. Two slots 58 and 59 are provided in the periphery of the contact wheel for respectively receiving the end portions of the pawls 38 and 39, under certain conditions, for connecting the wheel 21 to the plate 29 to effect engagement between the contact members 55 and 56 and the contact members 55 and 57. A pin 60 is mounted upon the plate 29 and projects within a slot 61 upon the wheel 31 fon returning the wheel to a neutral position after it has been operated to an extreme position by one of the pawls 38 and 39.

A lever 62, which is fulcrumed at 63, is provided with a bifurcated end portion 64 which engages a pin 65 mounted upon the wheel 31. The end of the lever 62 oppo site the bifurcated end portion 64 is provided with a collar 66 which surrounds a rod 67. The rod 67 is provided with two shoulders 68 and 69 which are disposed on opposite sides of the collar 66 and is pivotally connected to the trip arm 25. The lever arm 62 and the rod 67 serve to opcrate the arm 25 when the contactwheel 31 is in an extreme position for disengaging the trip member 28 from the dog 32 or the dog 33 to permit the dogs to retain the pawls 38 and 39 lILd'lOIIIlfl-l positions.

The switch 18 comprises a winding 70 which is connected across the supply conductors 16 and 17 upon engagement between the contact members 55 and 56. The winding 70 governs the operation of a switch arm 71 which carries'two contact members 7 2 and 73. Upon energization of the winding70, the arm 71 is operated to effect engagement between the contact member 72 and a stationary contact member 74 for connecting the armature 11 across the supply conductors 16 and 17 to effect counter-clockwise rotation of the motor 10. Upon release of the switch arm 71, the contact member 73 engages a stationary contact member 7 5 for completing a dynamic-braking circuit through thearmature 11.

The switch 19 comprises a winding 76 which is connected across the supply conductors 16 and 17 on engagement between the contact members 55 and 57 The Winding 7 6-controls a pivotally mounted switch arm 77 which carries two contact members 78 and 79. Uponener 'zation of the winding 76, the switch arm 7 is operated to effect engagement between the contact member 78 and a stationary contact member 80. Upon engagement between the contact members 78 and 80, a circuit is completed from the supply conductors 16 and 17 to the armature 11 for rotating the motor 10 in a clockwise direction. Upon release of the switch arm 77, 130

be in the position shown in the drawing and the motor 47 to be constantly rotating in a counter-clockwise direction and a current above normal value to flow'through the electrode 5, the energization of the main magnet 20 is increased to give the trip arm 25 a movement in clockwise direction. Thereupon, the trip member 28 is lowered to be in alinement with the top portion of the dog 32 and, as the plate 29 is oscillating toward the left by the counter-clockwise rotation of the motor 47, the dog 32 is moved in a clockwise direction to release the pawl 38 and permit such pawl to engage the slot 58 in the wheel 31. The return movement of the oscillating plate 29 carries the contact wheel 31 to effect engagement between the contact members 55 and 56.- When the contact wheel 31 reaches the neutral position, the pin 65 operates the lever 62 and the rod 67 to raise the trip member 28. Thus, the dog 32 is returned to normal position for retaining the pawl 38, when it is released from the wheel 31 by engagement with the pin 44. After the contact wheel 31 has been moved to an extreme right-hand position, the return movement of the wheel is effected by the pin 60 which operates within the slot 61. During the return movement, the lug .12 of the pawl 38 engages the stationary member 44. for raising the pawl from the slot 58. The dog 32 maintains the pawl 38 disengaged from the wheel 31 unless the trip member 28 has again been lowered by reason of a current abovenormal value flowing through the electrode 5.

Upon engagement between the contact members 55 and 56, during the operation above described, the switch 18 is operated for completing a'circuit through the armature 11 to effect counter-clockwise rotation of the motor 10. The counter-clockwise rotation of the motor 10 raises the electrode 5 to decrease the current flow through it. Upon release of the switch 18, by separationof the contact members 55 and 56, the contact member 73 engages the contact member for completing a dynamic-braking circuit which extends from the conductor 16 through contact members 73 and 75, armature 11, switch arm 7 7 and the contact members79 and 81 to the conductor 16. The above operation of the oscillating mechanism 21 and of the switch 18 is intermittently effected until normal current, flows through the electrode 5.

In case current below normal value flows through the electrode 5, the energization of the main magnet 20 is reduced for operating the trip arm 25 to raise the trip member 28.

Consequently, the trip member 28 is moved in alinement with the dog 33-, and the dog is operated for releasing the pawl 39 to connect the plate 29 with the contact wheel 31 to effect engagement between the contact members 55 and 57. Since the operation of the contact wheel 31 by the dog 33 and the pawl 39 is similar to the operation of the contact wheel by means of the dog 32 and the pawl 38, a detailed description of such operation is deemed unnecessary.

pon engagement between the contact members 55 and 57, the switch 19 is operated for completing a circuit through the armature 11 to effect clockwise rotation of the motor 10. The clockwise rotation of the motor 10 lowers the electrode 5 to increase the current flow through it. Upon release of the switch 19, the contact member 79 engages the contact member- 81 for completing a dynamic-braking circuit which extends from the conductor 16 through the contact members 79 and 81, switch arm 77, armature 1'1, switch arm 71 and the contact members 73 and 75 to the conductor 16. The switch 19 is intermittently operated by the oscillating member 21 and the magnet 20 until the current flow through the electrode 5 is raised to normal value.

, Modifications in the system and arrangement and location of parts may be made within the spirit and scope of my invention, and such modifications are intended to be covered by the apended claims,

-I claim as my invention:

1. In a furnace-regulator system, the combination witha movable electrode, a motor for operating the electrode, and control means for governing the direction of rotation and for effecting a quick stopping of the motor, of means controlled in accordance with the current flowing through the electrode and comprising a constantly oscillating member for governing said control means to maintain constant current flow through the electrode.

2. In a furnace-regulator system, the combination with a movable electrode, a motor for operating said electrode, and two switches for effecting rotation of said motor in a clockwise and in a counter-clockwise direction and for completing a motor dynamic-braking circuit under certain conditions, of means comprising a constantly oscillating member governed in accordance with the current flow through the electrode for controlling said switches to maintain a constant current flow through the electrode.

3. In a furnace-regulator system, the combination with a movable electrode, a motor for raising and lowering said electrode, and two switches for operating the motor in a clockwise and in a counter-clockwise direction and for com leting a dynamic-braking circuit through t e motor armature, of a magnet energized in accordance with the current flowing through the electrode, and means comprising an oscillating plate having trip members controlled by said magnet for selectively operating said-switches to maintain a constant current flow through the electrode.

4. In a furnace-regulator system, the combination with a movable electrode, a motor for operating the electrode, and means for controlling the direction of rotation of the motor and for completing a motor-braking circuit under certain conditions, of a magnet energized in accordance with the current flowing through the electrode, an oscillating plate and means controlled by said .magnet and said plate for governing said controlling means to maintain a constant current flow through the electrode.

5. In a furnac'reregulator system, the combination with a movable electrode, a motor for raising and lowering the electrode, and two switches for selectively rotating the m0- tor in a. clockwise and in a counter-clockwise direction and for establishing a braking circuit through the motor armature when simultaneously released, of a magnet operatedv in accordance with the current flowingv through the electrode, an oscillating plate carrying a. plurality of pawl and dog members, a contact arm, and means controlled by said magnet for selectively operating said dog to release the pawl members and to opcrate the contact arm for selectively operating one of said switches.

6. In a furnace-regulator system, the combination with a movable electrode, a motor for 1 operating said electrode, and two switches for efi'ecting rotation of said motor in a clockwise and in a counter-clockwise direction and for completing a motor dynamic-braking circuit, of a magnet operated in accordance with the current flowing through the electrode, and means comprising an oscillating member having a plurality of members controlled bv the magnet for selec tively; operating said switches to maintain constant current flow through the electrode.

7 In a furnace-regulator system, the combination with a movable electrode, a motor for operating said electrode, and two switches for controlling the direction of rotation of said motor, said switches completing adynamic-brakinq' circuit through the motor when simultaneously released, of means comprising a magnet operated in accordance with the current flowing through the electrode and a constantly oscillating member for controlling said switches to maintain a constant current flow through said electrode.

8. In a furnace-regulator system, the combination with a movable electrode, a motor for operating the electrode, and two switches for controlling the direction of rotation'of said motor, of means comprising a magnet energized in accordance with the current flowing through the electrode and a constantly oscillating member governed'b-y said magnet for intermittently operating said switches to maintain a constant current flow through the electrode.

9. In a furnace-regulator system, the combination with a movable electrode, an electric motor for operating said electrode, and switches for controlling thedirection of rotation of said motor, of means comprising a magnet energized in accordance with the current flowing through the electrode and a constantly oscillating member governed by said magnet for selectively and intermittently operating said switches to maintain a constant current flow through the electrode.

10. In a furnace-regulator system, the combination with a movable electrode, a constant oscillating member, andan electromagnet energized in accordance with the current flowing through 'said electrode, of means comprising a motor jointly controlled by.

said electromagnet and the oscillating member for controlling the current flow through said electrode, said means establishing a braking circuit through the motor under certain operating conditions. In testimony whereof, I have hereunto subscribed my name this 12th day of Aug. 1919.

CLARENCE A. BODDIE. 

